funding not secured

This is a hypothesis testing study, the hypothesis being that dietary supplements of n-PUFAs concentrates are anti-arrhythmic in ventricular arrhythmic substrates.

Study Aims: To investigate whether dietary supplements of n-3 polyunsaturated fatty acid concentrates (2g PUFAs/day, Omacor) reduces MTWA (a surrogate endpoint for ventricular arrhythmia substrate) in patients with ICDs for malignant ventricular arrhythmias.

Patients from the Department of Cardiology ICD out-patient clinic, Ninewells Hospital and Medical School, will be recruited. All these patients have a history of documented ventricular arrhythmia. Data from previous studies predict that 90% of these patients will have abnormal MTWA. A total of 45 ICD patients will be recruited. The study design will be a double blind randomised placebo controlled crossover design. A baseline MTWA test will be performed and patients with an abnormal test will be selected. The patients will be randomised to receive fish oil supplements (2g/day) or placebo for 8 weeks each. At the end of each intervention period, a repeat MWTA test will be performed. A 10 ml venous blood sampled will also be collected at baseline, and after each intervention period (3 samples in total). Patients in atrial fibrillation, frequent atrial or ventricular ectopics, or with ventricular pacing from the ICD, unstable angina, NYHA IV heart failure, pregnancy or child bearing potential will be excluded from the study.

End Points of the Study. The primary endpoint will be quantitative and qualitative measures of MTWA during n-3 PUFAs treatment compared to placebo.

Statistical Analysis: Quantitative differences in MTWA measurements will be analysed by a Student's t-test and qualitative differences by a chi squared test. A probability of 0.05% will be considered significant.

Inclusion Criteria:

• implantable cardiovertor defibrillators
• microvolt Twave alternans positive

Exclusion Criteria:

• unstable angina
• CHF